NOTE:This article was corrected to reflect that Alonso Mata's prison sentence was longer than one year.

On May 30, 24-year-old Paulina Ramirez-Diaz was found stabbed to death in her Nipomo home.

Six months later, the man once accused of ending her life received a sentence of just over two years in prison.

That's because the individual in question, 26-year-old Julio Caesar Alonso-Mata, wasn't convicted in connection with his former girlfriend's murder. Instead of standing trial for the murder in SLO County Superior Court, Alonso-Mata, an undocumented immigrant with prior criminal convictions, was convicted for violating federal immigration laws. Court documents showed that Alonso took a plea deal under a special program to help federal prosecutors and judges expedite such cases through a crowded court system.

Alonso-Mata was arrested by SLO County Sheriff's deputies and charged with Ramirez-Diaz's murder a short time after her body was discovered. In the wake of his arrest, investigators determined that Alonso-Mata was in the country illegally, and had been previously deported to Mexico in 2016.

"Considering the current state of the evidence, along with our burden of proof, 'beyond a reasonable doubt,' we are unable to proceed with prosecution at this time," SLO County Assistant District Attorney Lee Cunningham said shortly after the charges were dropped.

It wasn't long until federal immigration officials whisked Alonso-Mata away, and federal prosecutors in the U.S. Attorney's Office Central California District charged him with entering the United States illegally after previously being deported. Records in Alonso-Mata's federal immigration case showed that he'd run afoul of the law in the U.S. multiple times before he was arrested for his girlfriend's death. Those included felony convictions for methamphetamine possession, evading arrest, driving under the influence, vandalism, and commercial burglary in Santa Barbara County in 2012.

In August, Alonso-Mata entered into a plea deal with federal prosecutors, agreeing to plead guilty to the charge and receiving a sentence of 27 months in prison in November. According to court documents, that sentence is on the lower end of what Alonso-Mata could have received. While he is supposed to serve three years of supervised release after serving at least 85 percent of his sentence, he will more likely be deported back to Mexico by ICE officials instead.

The government's concession was made as part of a long-running immigration "fast track" early disposition plea program. The program was created in the 1990s to help border states like California deal with an increasing number of immigration cases. Under a fast track plea, a defendant agrees to plead guilty prior to their indictment, usually within 30 days after their arrest, in exchange for a lighter sentence, bringing the case to a faster resolution, and saving the courts time and resources.

"You agree to plead guilty very early in the case, and you get a reduced sentence," said Thom Mrozek, a spokesman for the U.S. Attorney's Office Central California District.

According to the United States Sentencing Commission, the country's federal courts handled 62,821 immigration cases in 2016. Of those cases, an estimated 96 percent were resolved via plea deals. While the commission's most recent report on immigration sentencing statistics does not state what percentage of those pleas were made through the fast track program, a 2015 report indicated that in the past the number has been as much as 28 percent.

Mrozek said that the Central California district has about 60 immigration cases each year that are resolved through fast track pleas. He added that the office offers fast track pleas to an estimated 90 percent of defendants in such cases.

"We agree that this is the best use of our resources to deal with these offenders," he said.

While the program's supporters argue that the fast track plea allows states like California to more efficiently handle a large number of immigration cases, others question whether it truly serves the interest of justice.

Last year, Southern California Federal Court Judge Larry A. Burns overturned a fast track plea in the case of a 52-year-old construction worker from Guadalajara who'd been arrested nine times for illegally entering the country, according to an investigation by San Diego news affiliate NBC 7.

"Seems to me that if a guy keeps doing the same thing ... one would think the penalties would go up, not down," Burns said at the time. "This isn't Starbucks where you get your eighth coffee for free."

Burns sentenced the man to 45 months in prison.

While Alonso-Mata begins serving his sentence on the immigration charges, the investigation into his girlfriend's murder remains open. There are no charges filed against anyone else in connection to Ramirez-Diaz's death, and Alonso-Mata remains a "person of interest" in the case, according to officials from the SLO County District Attorney's Office. Δ